This invention relates to certain cyclic di-esters of known .beta..sub.2 -agonists, which di-esters possess favorable properties for the treatment of asthma and all types of chronic obstructionary pulmonary diseases (COPD).
.beta..sub.2 -agonists are well known in the art, e.g. albuterol which is described in U.S. Pat. No. 3,644,353. Certain esters of albuterol or compounds closely related to albuterol have also been described, e.g. in U.S. Re. Pat. No. 30 241, British Patent No. 1,298,771, U.S. Pat. No. 3,904,671. However, none of these publications describe or suggest the cyclic di-esters of this invention.